Articles | Volume 1, issue 2
https://doi.org/10.5194/soil-1-509-2015
https://doi.org/10.5194/soil-1-509-2015
Original research article
 | 
10 Jul 2015
Original research article |  | 10 Jul 2015

Gully geometry: what are we measuring?

J. Casalí, R. Giménez, and M. A. Campo-Bescós

Abstract. Much of the research on (ephemeral) gully erosion comprises the determination of the geometry of these eroded channels, especially their width and depth. This is not a simple task due to uncertainty generated by the wide range of variability in gully cross section shapes found in the field. However, in the literature, this uncertainty is not recognized so that no criteria for their measurement are indicated. The aim of this work is to make researchers aware of the ambiguity that arises when characterizing the geometry of an ephemeral gully and similar eroded channels. In addition, a measurement protocol is proposed with the ultimate goal of pooling criteria in future works. It is suggested that the geometry of a gully could be characterized through its mean equivalent width and mean equivalent depth, which, together with its length, define an "equivalent prismatic gully" (EPG). The latter would facilitate the comparison between different gullies.

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Short summary
Despite gullies having been intensively studied in the past decades, there is no general consensus on such basic aspects as the correct determination of the geometry (width and depth) of these erosion features. Therefore, a measurement protocol is proposed to characterize the geometry of a gully by its effective width and effective depth, which, together with its length, would permit the definition of the equivalent prismatic gully (EPG); this would facilitate the comparison between gullies.